Scoped registry review fixes

packages/scoped-custom-element-registry/CHANGELOG.md

@@ -25,6 +25,22 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   null registry
 - `HTMLElement`, and classes extending it, inherit the statics of `Element`
   and `Node` (e.g. `ELEMENT_NODE`)
+- `new X()` gives the element the global registry
+- `importNode` reads its options as WebIDL does: null or an object is a
+  dictionary, anything else a boolean
+- A registry argument that isn't a `CustomElementRegistry` throws a
+  `TypeError`
+- `define`, `get` and `whenDefined` convert the name to a string
+- An element is customized at most once; as natively, a failed upgrade clears
+  its definition, and a constructor that throws before `super()` leaves it an
+  `HTMLElement`
+- `attachInternals` throws for an element that isn't customized
+- Form callbacks run on upgrade, and only for form-associated elements
+- Initial `attributeChangedCallback`s run in attribute order
+- An insertion that throws restores the registries it changed
+- `Document` `append`/`prepend`/`replaceChildren`, `CharacterData`
+  `before`/`after`/`replaceWith`, `textContent`, `innerText`, `outerText` and
+  `setHTML` keep registries
 
 ### Changed
 

packages/scoped-custom-element-registry/DESIGN.md

@@ -89,7 +89,8 @@ registry.
 Moving a node into another document changes null and global registries as
 the spec says, to an _effective global registry_: the new document's global
 registry, or null if the document's registry is scoped. Scoped registries are
-kept. Patched insertion methods apply this before the native move.
+kept. Patched insertion methods apply this before the native move, and undo
+it if the move throws.
 
 The polyfill's state is shared by same-origin windows, so nodes moved between
 them work as natively.

packages/scoped-custom-element-registry/README.md

@@ -134,8 +134,9 @@ Tests of these are skipped when the browser's native support is used.
     one;
   - a copy of an element with a global registry, in a document with a scoped
     registry, gets that scoped registry instead of null;
-  - `ElementInternals.setFormValue` works for an element whose constructor
-    failed, which isn't form-associated;
+  - an element whose constructor failed keeps its definition, so
+    `ElementInternals.setFormValue` still works for it, and it can't attach a
+    shadow root if its class disables them;
   - adopting a null-registry element gives it the document's registry,
     instead of its new parent's (as an effective global registry);
   - adopting a host gives its shadow root a null registry but leaves the